For many applications of painting robots it is desirable to be able to change color quickly, e.g. in automobile painting.
During color change, the supply volume between a colour changing equipment and the paint spraying device has to be emptied of the previously used paint and thoroughly cleaned with a cleaning liquid before new paint can be supplied. This volume is mostly made up by the supply lines between the changing equipment and the spraying device.
In other applications of painting robots, two-component paints are used. These components have to be mixed immediately before application. After finishing a paint application cycle, the supply volume filled with mixed paint has to be quickly emptied and thoroughly cleaned with cleansing liquid. Fast reacting two-component paints may already have started to cure during the preparation for cleaning thereby making cleaning more difficult.
FIG. 1 shows a painting robot of the prior art. The color changing equipment or the two-component mixing equipment is placed at the lower part of the robot in order to ensure short supply distances without having the color changer etc. interfering with the operational precision of the robot arm.
For both color change and two-component applications, the large volumes of waste paint that accumulate constitute a problem due to their environmental impact and the cost of the waste paint.